Keeping the Sea Safe from Plastic

The Great Pacific Garbage Patch, a vortex of trash in the North Pacific, spans hundreds of miles. The waste, much of it plastic, is suspended like confetti under the waves and on the surface. “It’s so dilute, it’s probably impossible to clean up,” says Henry Carson, a professor of Marine Science at the University of Hawaii. “Our best bet is to start by not putting any more plastic in.”

Keeping litter out of the ocean isn’t easy, though, and most biodegradable plastics don’t break down well in marine environments—they require the relative warmth of soil or a compost heap. A new plastic on the market degrades quickly both on land and in seawater. Polyhydroxyalkanoate plastic, better known as PHA, has been around in labs for decades but became commercially available only in October 2010 through a joint venture between Cambridge (Mass.) startupMetabolix (MBLX)andArcher Daniels Midland (ADM). In the past year, 57 companies, including PaperMate and Cortec, started using the Mirel-brand plastic to manufacture products like pens, packaging, and fishing nets. “It’s like a miracle material,” says Jo Ann Ratto, a polymer research engineer with the U.S. Army who has studied the plastic.

PHA is produced by bacteria, which use it to store energy in the same way that humans store energy as fat. It will degrade in any microbe-rich environment because bacteria recognize the material as food and gobble it up. “If a bag made from PHA plastic is put into a natural lake, the ocean, a home compost facility, the woods, or any place where there are natural microbes present, they will consume it and it will disappear,” says Richard P. Eno, chief executive officer of Metabolix.